Weight controlled grinder and method of grinding coffee beans

ABSTRACT

A coffee grinding apparatus which includes a coffee bean grinding mechanism and a weighing device associated with the grinding mechanism to weigh ground coffee. A receptacle is associated with the weighing device and positioned below the grinding mechanism for receiving ground coffee from the grinding mechanism. The weighing device generates an actual weight signal corresponding to the weight of the ground coffee dispensed into the receptacle. A selecting device is provided to allow a user to select a weight of ground coffee to be produced by the apparatus. A dispensing assembly may be associated with a whole bean hopper, the selecting device and weighing device are coupled to a control circuit which controls the grinding apparatus. The control circuit operates the dispensing assembly and/or the grinding mechanism as a function of a comparison of the actual weight signal and the selected weight signal. As the relationship between the selected weight signal and actual weight signal approaches parity, the control circuit controls to dispensing assembly and/or grinding mechanism to controllably approach the selected weight of ground coffee.

INVENTORS

John T. Knepler, RR 1, Box 182, Chatham, Ill. 62629

William E. Midden, 2036 S. Spring St., Springfield, Ill. 62704

David F. Ford, 3313 Ivyton Dr., Springfield, Ill. 62704

BACKGROUND

The present invention relates to a coffee grinding apparatus whichproduces a selected weight of ground coffee.

A variety of coffee grinding apparatus are available which weigh aquantity of whole coffee beans to be ground or which measure a desiredquantity of whole coffee beans as a function of time. For example, U.S.Pat. No. 4,789,106 to Weber, issued Dec. 6, 1988, provides a grindingapparatus having a pair of hoppers in a gravity feed relationship with agrinding mechanism. Whole coffee beans are dispensed from the hoppersonto a bean bucket which mechanically weighs the whole beans prior togrinding. When a quantity of whole beans has accumulated on the beanbucket, the bean bucket tips and drops the whole beans into the grindingmechanism.

A problem with the device as shown in Weber, and other devices of thistype, is that the beans are weighed in the whole coffee bean form priorto grinding and therefore cannot compensate for the size, density,oiliness and other characteristics of the beans. It is important toconsider these characteristics in measuring ground coffee since thesecharacteristics affect the weight of the ground coffee.

In producing brewed beverages it is important to maintain theconsistency of the flavor of beverages produced by the brewing machine.Customers appreciate a predictably good tasting cup of coffee. A keyfactor in maintaining consistency in brewing beverages is maintainingthe proper amount of ground coffee used in the infusion process.Maintaining the proper amount of coffee is also important to coffeevendors to economically manage and efficiently utilize ground coffee.The flavor of a brewed beverage such as coffee may require maintaining atolerance for the measurement of the ground coffee within +/-0.1 ounce.Such precise measurement tolerances require highly accurate measuringcontrols.

With regard to the device in Weber, the device measures whole beans andtherefore may not be able to maintain the +/-0.1 ounce weighingtolerance. The device in Weber allows beans to flow from a hopper untila predetermined weight is sensed by the bean bucket. When thepredetermined weight of whole beans is sensed, a hopper gate between thehopper and bean bucket is closed. In view of the beans being in a wholebean state, the measurement may be inaccurate since numerous whole beansmay be dispensed from the hopper after the desired weight is sensed. Theproblem of measuring beans using a device as shown in Weber isexacerbated when the whole beans have an oily characteristic such as isfound in dark roast beans, especially, french or espresso roast beans.The oiler beans tend to cling to each other thereby almost assuring aninaccurate measurement.

Another problem with accurately weighing ground coffee is that manycoffee grinding apparatus which combine a storage hopper and adispensing mechanism rely on volume based measurement to dispense aweight of coffee beans. For instance, in a device combining a storagehopper with an auger to dispense beans from the hopper, the grindingdevice will dispense a predetermined volume of coffee to be ground, incontrast to traditional coffee measuring methods in which coffee ismeasured by weight. When beans are of a consistent density, a timed orvolume measuring mechanism will generally yield a fairly accurate weightmeasurement. In reality, coffee beans often vary in density due tovariations in the type of bean, the roast of the bean, and/or blending.These variations may occur even within a single brand or type of coffee.Such measuring and grinding apparatus may not achieve the desiredtolerance where precision weight control is required.

In view of the foregoing problems and requirements, there is a need fora grinding apparatus which precisely dispenses a desired weight ofground coffee regardless of the characteristics of the whole coffeebeans being ground.

OBJECT AND SUMMARY

A general object of the present invention is to provide a coffeegrinding apparatus which precisely grinds and dispenses a selectedweight of ground coffee.

Another object of the present invention is to provide a coffee beangrinding apparatus which supports a receptacle in close proximity to agrinding mechanism which dispenses ground coffee.

Yet another object of the present invention is to provide a coffee beangrinding apparatus which provides a receptacle support structure whichaccommodates a wide variety of receptacle dimensions.

A further object of the present invention is to provide a coffee beangrinding apparatus which employs multiple hoppers and multiple grindingmechanisms, each mechanism being associated with a corresponding hopper,and provides precise control of the grinding mechanisms.

Still a further object of the present invention is to provide a methodof grinding coffee beans to produce a selected weight of ground coffee.

An additional object of the present invention is to provide a novelweight sensor for weighing ground coffee.

Briefly, and in accordance with the foregoing, the present inventionenvisions a coffee grinding apparatus which includes a coffee beangrinding mechanism and a weighing device associated with the grindingmechanism to weigh ground coffee. A receptacle is associated with theweighing device and positioned below the grinding mechanism forreceiving ground coffee from the grinding mechanism. The weighing devicegenerates an actual weight signal corresponding to the weight of theground coffee dispensed into the receptacle. A selecting device isprovided to allow a user to select a weight of ground coffee to beproduced by the apparatus. A dispensing assembly may be associated witha whole bean hopper, the selecting device and weighing device arecoupled to a control circuit which controls the grinding apparatus. Thecontrol circuit operates the dispensing assembly and/or the grindingmechanism as a function of a comparison of the actual weight signal andthe selected weight signal. As the relationship between the selectedweight signal and actual weight signal approaches parity, the controlcircuit controls to dispensing assembly and/or grinding mechanism tocontrollably approach the selected weight of ground coffee.

BRIEF DESCRIPTION OF THE DRAWINGS

The organization and manner of the structure and operation of theinvention, together with further objects and advantages thereof, may beunderstood by reference to the following description taken in connectionwith the accompanying drawings, wherein like reference numerals identifylike elements, and in which:

FIG. 1 is a diagrammatic representation of a coffee bean grindingapparatus of the present invention;

FIG. 2 is a diagrammatic representation of a coffee bean grindingapparatus of the present invention employing two hoppers and multiplegrinding mechanisms, each grinding mechanism being associated with acorresponding hopper;

FIG. 3 is a front elevational view of a grinding apparatus of thepresent invention;

FIG. 4 is a side cross-sectional view taken along 4--4 in FIG. 3;

FIG. 5 is a detailed, partial fragmentary, cross-sectional plan view ofan augering dispensing assembly for use with the grinding apparatus ofthe present invention;

FIG. 6 is a partial fragmentary, cross-sectional side elevational viewtaken along line 6--6 in FIG. 5 of the dispensing assembly;

FIG. 7 is a front elevational view taken along line 7--7 in FIG. 5showing a discharge regulator attached to a dispensing end of thedispensing assembly;

FIG. 8 is a partial fragmentary, cross-sectional plan view taken alongline 8--8 in FIG. 3 of a weighing device employed in the coffee grindingapparatus;

FIG. 9 is a partial fragmentary, side elevational view taken along line9--9 in FIG. 8 of the weighing device;

FIG. 10 is a perspective view of alternate configuration of the weighingdevice;

FIG. 11 is a general flow chart showing the control of the coffeegrinding apparatus; and

FIG. 12 is an enlarge, partial fragmentary, cross-sectional side viewtaken along line 12--12 in FIG. 4 of the weight sensor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While the invention may be susceptible to embodiment in different forms,there is shown in the drawings, and herein will be described in detail,an invention with the understanding that the present description is tobe considered an exemplification of the principles of the invention andis not intended to limit the invention to that as illustrated anddescribed herein.

FIG. 1 shows a coffee grinding apparatus 20 of the present invention.The coffee grinding apparatus 20 includes means for dispensing beans ordispenser 22 operatively associated with a grinding mechanism 24 whichgrinds whole coffee beans and dispenses the ground coffee into areceptacle 26. The receptacle 26 is cooperatively associated with means28 for weighing the ground coffee dispensed from the grinding mechanism24 into the receptacle 26. A control circuit 30 is provided and iscoupled or interfaced with several components including: the dispenser22 by way of line 32; the weighing means 28 over line 34; and thegrinding mechanism 24 over line 36.

The coffee grinding apparatus 20 produces a precise weight of groundcoffee corresponding to a weight of coffee selected by a user. Thecontrol circuit 30 includes means 38 for selecting a desired weight ofground coffee to be produced by the apparatus 20, also referred to asselector 38. The selector 38 in combination with the control circuit 30produces a selected weight signal which is compared to an actual signalgenerated by the weighing means 28 in order to determine whether theground coffee produced by the grinding apparatus 20 is approaching orapproximately equal to the desired selected weight of ground coffee. Thecontrol circuit 30 operates the dispenser 22 and/or the grindingmechanism 24, as a function of the selected weight compared to theactual weight of ground coffee.

More specifically, a user selects a desired weight of ground coffeeusing the selector 38, the dispensing means 22 dispenses whole coffeebeans into the grinding mechanism 24 which then grinds the whole beansand discharges ground coffee into the receptacle 26. During the grindingoperation, the weighing means 28 repeatedly weighs the ground coffeewhich accumulates in the receptacle 26 and transmits the actual weightsignal to the control circuit 30 over line 34. The actual weight signalis compared to the selected weight of ground coffee to be produced. Asthe weight of the ground coffee sensed at the weighing means 28approaches the desired selected weight of ground coffee, the controlcircuit 30 controls the dispenser 22 and/or the grinding mechanism 24 tocontrollably approach the selected weight. The control circuit 30controls the dispenser 22 by decreasing the rate at which beans aredispensed into the grinding mechanism 24 so that the selected weight ofground coffee is produced within a predetermined tolerance range. Thecontrol circuit controls the grinding mechanism 24 by slowing orstopping the grind operation.

As shown in FIG. 1, the dispenser 22 includes a pair of hoppers 40,42and a dispensing assembly 44 associated with each hopper 40,42. Thedispensing assembly 44 shown diagrammatically will be discussed ingreater detail hereinbelow with reference to FIGS. 5 and 6. The grindingmechanism 24 is of known construction such as a burr grinder which canbe set to produce a desired ground coffee particle size. The receptacle26 can take the form of a container which is used to capture the groundcoffee dispensed from the grinding mechanism 24 or, as is moredesirable, is a brewing funnel. As will be described herein in greaterdetail with reference to FIGS. 8-10, a support structure 46 is providedto accommodate a variety of funnel sizes. As shown in FIG. 1, the means28 for weighing is positioned below the receptacle 26. The diagrammaticillustrations of FIGS. 1 and 2 should not be construed to limit theposition of the weighing means 28 to a location below the receptacle 26.To the contrary, FIGS. 8 and 9 position a weight sensor 48 of theweighing means 28 in a location other than below the receptacle 26 totake advantage of a mechanical relationship associated with the funnelsupport structure 46 shown therein.

The control circuit 30 includes circuitry which compares a signal fromthe weighing means 28 to a signal from the selecting means 38 in aniterative process to control the dispensing assembly 44 and/or thegrinding mechanism 24 in relation to the weight of the ground coffeeaccumulating in the receptacle 26. During use, when the receptacle 26 isinitially associated with the weighing means 28, the control circuit 30"tares" the weight of the receptacle 26 so as to establish a zero pointfor weighing the ground coffee dispensed into the receptacle 26. Inother words, only the weight of the ground coffee will be weighed andnot the additional weight of the receptacle 26.

The control circuit 30 also includes means for storing presetselections. The preset selections are in the form of a selected weightof ground coffee which corresponds to the tare weight of a receptacle26. The tare weight is the weight of the receptacle which is initiallysensed by the weighing means 28 during the tare operation. In thisregard, the control circuit 30 provides automatic recognition of areceptacle or funnel 26 engaged with the funnel support structure 46.This feature is useful when a user has multiple brewing apparatus orbrewers of different sizes, each brewer employing a different sizefunnel. The control circuit 30 is programmed to store selected weightscorresponding to each of the different funnels. As such, when a funnelis engaged with the funnel support structure 46, the weighing means 28senses the weight of the funnel and generates a signal over line 34 tothe control circuit 30. The control circuit 30 then automaticallyselects the weight of ground coffee for comparison to the actual weightof the accumulating ground coffee. This feature allows a user to place afunnel in the funnel support structure and automatically receive aprecisely weighed charge of ground coffee for use with brewer associatedwith the funnel.

As an additional feature, the function of the selecting means 38 isdistributable to a companion brewer (brewer not shown) by coupling thecontrol circuit 30 to the brewer over control line 50. As such, adesired volume of beverage can be selected at the brewer therebygenerating a signal transmitted over line 50 to the control circuit 30.The storage means retains a selected weight associated with the selectedvolume and employs this selected weight for comparison to the actualweight of the accumulating ground coffee to control the apparatus 20.

In a similar manner to the operation of the apparatus 20 as discussedwith reference to FIG. 1, the apparatus 20 as shown in FIG. 2 operatesby selecting a desired weight at the selection means 38 and iterativelycomparing the weight of ground coffee dispensed into the receptacle 26to the selected weight. The corresponding grinding mechanism 24a,24b iscontrolled as a function of the iterative comparison.

With reference to FIGS. 2-4, the coffee grinding apparatus 20 isessentially the same as that as shown in FIG. 1 with the addition of twoindependent grinding mechanisms 24a and 24b. Each grinding mechanism24a,24b is controlled over a separate control line 36a,36b coupling thegrinding mechanisms 24a,24b to the control circuit 30. The use of twoindependent grinding mechanism 24a,24b eliminates any possibility ofmixing any portion of ground coffee dispensed therefrom. A problem whichprevented use of two independent grinding mechanisms 24a,24b in theprior art is that grinding mechanisms use an AC inductive motor of atleast 1/3 horse power. If two such AC motors were used, the overallwidth of the grinding apparatus 20 would be undesirable. As such, thepresent invention uses two permanent magnet DC motors which have hightorque capabilities to satisfy the grinding requirements associated withgrinding whole coffee beans. The outside dimensions of the permanentmagnet DC motors 52 are much smaller than the AC motor and areconveniently controllable by way of the control circuit 30.

With further specific reference to FIGS. 3 and 4, the coffee grindingapparatus 20 is configured with two hoppers 40,42 and two grindingmechanisms 24a,24b. The dispensing means 22 is provided by the gravityfeed relation of the hoppers 40,42 with the respective grindingmechanisms 24a,24b. The configuration as shown in FIGS. 3 and 4 does notinclude a mechanical dispensing assembly 44. This configurationcontrollably grinds the precise weight of ground coffee selected at theselector 38 by controlling the grinding mechanisms 24a,24b. In use, theuser selects a weight and type of bean to be ground at the selector 38.The control circuit 30 operates the appropriate grinding mechanismassociated with the user selection. The grinding mechanism is activatedand is slowed or deactivated as the actual weight sensed by the weighingmeans 28 and the selected weight approach parity.

With reference to FIG. 11, the weight sensor 48 of the weighing means 28provides an analog voltage output 34' which is passed to an amplifier 53which scales and level shifts the signal. The amplified signal 53'generated by the amplifier 53 is fed to an analog to digital converter54 (ADC) which then produces a digital output signal 54' representingthe weight of ground coffee which has accumulated. This signal 54' isutilized by a microprocessor 55 of known construction having memorycapabilities for storing preset selections. The selector 38 as shown inFIG. 11 includes a keyboard and display 56,57. The keyboard 56 is usedto enter or select a desired weight of ground coffee to be produced bythe grinding apparatus 20. The selector 38 both transmits information to(line 38') and receives information from (line 38") the microprocessor55. The microprocessor 55 controls the grinding mechanism 24 and thedrive motor 66 of the drive mechanism 64.

Having described the overall structure and embodiment of the coffeegrinding apparatus 20 of the present invention, we shall now refer toFIGS. 5-11 to discuss further details of the dispensing assembly 44,support structure 46, weighing means 28, and weight sensor 48.

The dispensing assembly 44 includes sloped hopper walls 58 whichcommunicate with a dispensing tube 59. The hoppers 40,42 and dispensingtube 59 are of a known construction, such as is shown in U.S. Pat. No.5,277,337 to Ford et al. The sloped hopper walls 58 promote the flow ofwhole beans from the hopper into a receiving end 60 of the dispensingtube 59. An auger 61 is retained in the dispensing tube 59 extendingfrom the receiving end 60 to a dispensing end 62. The auger 61 isconnected to a drive mechanism 64 which rotates the auger 61 in thedispensing tube 59 to advance beans through the tube 59 towards thedispensing end 62.

The drive mechanism 64 includes a drive motor 66 and a gear assembly 68.The gear assembly 68 is positioned outside of the whole bean flow pathso as to prevent grinding or damaging whole beans which are advanced bythe auger 61. The auger 61 includes a primary drive section 70 and asecondary drive section 72. The primary drive section 70 has an outsidediameter of approximately 3/4" while the secondary drive section 72 hasa diameter of approximately 1/2"-5/8". The pitch of the secondary drivesection 72 is slightly greater than the primary section 70 so as to keepthe feed ratio approximately the same along the two sections 70,72.Maintaining a generally equal feed ratio provides a generally constantflow of whole beans through the dispensing tube 59. The reduced diametersection of the secondary drive section 72 eliminates jamming or catchingof beans on the inside of the dispensing tube 59 near the dispensing end62. The reduced diameter provides greater clearance between the outsideof the auger 61 and the inside of the dispensing tube 59.

With reference to FIGS. 5-7, a discharge regulator 76 is placed over thedischarge end 62 of the dispensing tube 59. The discharge regulator 76is a resilient cap which is secured to the dispensing tube 59 having afront face 78 overlying the open end of the dispensing end 62 and havinga plurality of slits 80 formed through the face 78. The slits 80 incombination with a tip 82 of the auger 61 extending through the slits 80allow beans to be discharged from the dispensing tube 59 and into thegrinding mechanism 24. The discharge regulator 76 prevents beans fromdribbling or uncontrollably flowing out of the dispensing tube 56 underthe influence of vibrations from the grinding mechanism 24. Theprotrusion of the tip 82 through the slits 80 increases the size of theopening while the auger 60 is being driven thereby creating a largeropening to drive the beans through and thereby preventing forcedejection of beans through the resilient surface 78 of the regulator 76.

In use, the drive mechanism 64 of the dispensing assembly 44 isconnected or interfaced by way of line 32 to the control circuit 30. Thecontrol circuit 30 slows down the drive mechanism 64 as the actualweight of ground coffee sensed by the weighing means 28 approachesparity with the selected weight to be ground. By slowing down the auger61, the weighing means 28 precisely senses the approaching selectionweight. Additionally, by slowing down the auger speed, the grindingmechanism catches up and eliminates any backlogged beans and operates ina "starved grinder" mode. In other words, the grinding mechanism 24grinds beans as soon as they are dispensed from the dispensing assembly44. This prevents grinding beans after the selected weight is sensed bythe weighing means 28.

FIGS. 8 and 9 provide a plan and side elevational view of the weighingmeans 28 which includes the support structure 46 and the weight sensor48. FIG. 9 is a simplified illustration of the weighing means 28 so asto assist in clarifying the basic principle of the weighing means 28. Asshown in FIGS. 3 and 4, the support structure 46 and weight sensor 48are operatively associated with a fixed structure or mounting bracket 84of the grinder apparatus housing. The support structure 46 includes apair of pivotable arms or curved rails 86 operatively attached to alever member 88 which is hingedly attached by way of a hinge assembly 90to the bracket 84. An attachment member 92 of the curved rails 86engages a pivot post 94 which depends from the lever member 88. A freeend 96 of the attachment member 92 extends beyond the pivot post 94. Aspring 98 is attached at one end to the free end 96 and at an oppositeend to the lever member 88. The spring 98, in combination with thepivotable post 94, provides a biasing effect to help maintain a minimumopening between distal ends 100 of the rails 86.

With reference to FIG. 12, the weight sensor 48 of the weighing means 28is shown in an enlarged, partial fragmentary, cross-sectional view. Theweight sensor 48 includes a housing 101 and a cover 103 which areattached to the bracket 84. A hollow area inside the housing 101 andcover 103 defines a cavity 105. An upper end of the cavity 105 is sealedby a resilient flexible diaphragm 107 and a lower portion of the cavityis sealed by a pressure sensing device 109 and a sealing gasket 112. Aliquid 114 is retained in the cavity 105 between the diaphragm 107 andthe pressure sensing device 109 and gasket 112. A contact body 113including a crown 115 attached to a base 116 is retained between thecover 103 and the diaphragm 107. The base 116 abuts the diaphragm 107and the crown 115 extends through the cover 103. Weight is applied tothe tip of the crown 115 and transmitted as a pressure or force throughthe base 116 and diaphragm 107 to the incompressible liquid 114.

The pressure sensing device 109 is biasedly retained in the lowerportion of the cavity 105 by a biasing plate 118 positioned immediatelybelow a body structure 120 of the pressure sensing device and aretaining spring 122 which is held against the biasing plate 118 by aretaining bracket 124 connected to the bracket 84 by way of retainingrod 126. The liquid in the cavity 114 is generally incompressible and isselected to be compatible with the surrounding materials such as thematerial used to form the housing 101 and the diaphragm 107. In order toensure the incompressibility of the liquid 114, the cavity 105 filledwith the liquid 114 can be evacuated of air in a vacuum chamber prior tosealing the weight sensor 48.

The sensing device 109 is held against the gasket 112 by a retainingspring 122. The retaining spring 122 is sized to preload the sensingdevice 109 above the working pressure of the monolithic sensor retainedtherein. The retaining spring 122 is part of a relief valve assemblywhich prevents damage to the pressure sensing device 109. The spring 122is sized so that if an overload condition is put on the sensing device109, the spring 122 will give and act as a pressure relief valve andallow the seal between the sensor body 120 and gasket 112 to disengageand leak fluid 114 thereby relieving any excess pressure. The reliefvalve feature of the weight sensor 48 prevents damage to the sensingdevice 109 by bleeding off liquid to reduce excessive pressure.

The pressure sensing device 109 is of known construction such as amonolithic silicone piezoresistor pressure sensor as produced byMotorola Corporation. The pressure sensing device 109 generates achanging output voltage with variations in applied pressure. The outputvoltage is directly proportional to the pressure applied to the sensingdevice 109.

The weight sensor 48 functions to sense a weight and convert the sensedweight to an analog electrical signal proportional to the given weight.As the weight is applied at the crown 115 in a direction generallyperpendicular to a central axis 128 of the sensor 48, the diaphragm 107builds pressure in the liquid 114 retained in the housing 101 equal tothe actual weight divided by the area of the exposed diaphragm 107. Thepressure is sensed by the pressure sensing device 109, which produces ananalog voltage output proportional to the pressure sensed within theweight sensor 48. The actual total maximum volumetric change is quitesmall, for example 0.001 cubic inches. The total full scale weightactual movement of the diaphragm 107 is equal to the volume changedivided by the area of the diaphragm 107, if an incompressible liquid114 is used.

The use of the incompressible liquid evacuated of air and all othergases ensures minimum diaphragm movement. This characteristic isdesirable so that as ground coffee is discharged into the receptacle,the lever member 88, resting on top of the crown 115, moves through analmost imperceptible range of movement. The extremely small range ofmovement of the lever member 88 minimizes or essentially eliminates anyfriction in the pivot point of the hinge assembly 90. As such, aprecision bearing assembly is not required.

In use, a funnel 26 is placed through the opening between the distalends 100 of the rails 86 overcoming the biasing effect of the spring 98and is retained between the curved areas 102 of each rail 86. Since thelever member 88 is hinged at one end by the hinge assembly 90 andbecause the weight sensor 48 is positioned underneath the lever member88, the weight of the funnel 26 retained on the curved rails 86 exerts aforce on the weight sensor 48 thereby generating a weight signal overline 34 to the control circuit 30. The control circuit 30 uses the emptyweight of the funnel as a tare weight thereby establishing a zeroreference point which is used to weigh the ground coffee which iscollected in the funnel 26. As ground coffee is deposited into thefunnel 26, a proportionate amount of weight is applied to the weightsensor 48. An analog electrical signal corresponding to the sensedweight is generated by the sensor 48.

With reference to FIG. 10, an alternate embodiment of the funnel supportstructure 46a is shown. It should be noted that structures whichfunction in generally the same manner will be identified using the samereference numerals with the addition of an alphabetic suffix. Forexample, the curved rails in FIG. 8 are identified with referencenumeral 86 whereas in FIG. 10, they are identified with referencenumeral 86a. The curved rails 86a are spaced apart and lie in agenerally horizontal plane attached to vertically oriented legs 104. Thelegs 104 are dimensioned to locate the uppermost edge of the curvedrails 86a to position a funnel retained thereon proximate to a dischargechute 106 of the grinding apparatus 20. The legs 104 are attached to aweight sensor 48a which senses the weight of objects placed on aweighing surface 108. The weight of a funnel 26 retained on the rails86a is transferred to the weight sensor 48a to sense a tare weight priorto discharging ground coffee into the funnel 26. As ground coffeeaccumulates in the funnel, the weight sensor 48 senses the increasingweight and provides a signal over line 34 to the control circuit 30. Thesupport structure 46a is constructed so that the rails 86a can moveoutwardly away from each other (see arrows 110) to accommodate funnelsand receptacles of greater diameter. Springs 98a are provided along thelegs 104 to provide a biased pivoting point to provide biasingdisplacement.

In use, the present invention dispenses whole coffee beans from storagehoppers 40,42 into one or more grinding mechanisms 24 for grinding anddispensing into a receptacle or funnel 26. The weight of the groundcoffee is weighed or sensed by the weighing means 28. The controlcircuit 30 provides precise control of the dispensing means 22 and/orthe grinding mechanism 24 so that only a precise selected weight ofground coffee is produced and dispensed into the receptacle 26.

A user operates the grinding apparatus 20 by selecting, at the selectingmeans 38, a weight of ground coffee to be produced. The weight of thereceptacle 26 retained on the support structure 46 is tared so as toprovide a zero reference point to weigh the ground coffee. Once grindingis initiated, the weighing means 28 senses the weight of the groundcoffee dispensed into the receptacle and, since it is interfaced withthe control circuit 30 over line 34, provides a signal corresponding tothe weight of the accumulated ground coffee. The control circuit 30compares the actual weight signal to the selected weight signal andoperates the dispensing means 22 and/or grinding mechanism 24 inresponse to the comparison. As the two signals, the actual weight signaland the selected weight signal, approach parity, the dispensing means 22is controlled to slow the feed rate of whole beans to the grindingmechanism 24 or the grinding mechanism 24 is deactivated.

When using the embodiment employing the dispensing assembly 44, thecontrol means 30 operates the dispensing assembly 44, such as is shownin FIGS. 5 and 6, to dispense whole beans into the correspondinggrinding mechanism. As the actual weight signal and selected weightsignal approach parity, the control signal 30 Slows the dispensing rateof the dispensing assembly 44 such that the actual weight of the groundcoffee controllably approaches the selected weight and thereby provide aprecise measurement of ground coffee.

While a preferred embodiment of the present invention is shown anddescribed, it is envisioned that those skilled in the art may devisevarious modifications of the present invention without departing fromthe spirit and scope of the appended claims. The invention is notintended to be limited by the foregoing disclosure.

The invention claimed is:
 1. A method of grinding coffee beans forproducing a selected weight of ground coffee comprising the stepsof:generating a selected weight signal corresponding to a selectedweight of ground coffee to be produced; dispensing coffee beans into agrinding mechanism; discharging ground coffee from said grindingmechanism to a receptacle; generating an actual weight signalcorresponding to the weight of ground coffee collected in saidreceptacle; comparing said actual weight signal to said selected weightsignal during the grinding of coffee beans by said grinding mechanism;decreasing the dispensing rate of beans into the grinding mechanism inresponse to a comparison of said actual weight signal and said selectedweight signal as said actual weight signal and said selected weightsignal achieve parity; ceasing dispensing of coffee beans into saidgrinding mechanism prior to achieving said selected desired weight ofground coffee; and operating said grinding mechanism for a period oftime after ceasing dispensing of coffee beans.
 2. A method of grindingcoffee beans for producing a selected weight of ground coffee comprisingthe steps of:generating a selected weight signal corresponding to aselected weight of ground coffee to be produced; starting a grindingmechanism; dispensing coffee beans into said grinding mechanism;discharging ground coffee from said grinding mechanism to a receptacle;generating an actual weight signal corresponding to the weight of groundcoffee collected in said receptacle; comparing said actual weight signalto said selected weight signal during the grinding of coffee beans bysaid grinding mechanism; and controlling the discharging of groundcoffee from the grinding mechanism as the comparison of said actualweight signal and said selected weight signal approach parity.
 3. Acoffee grinding apparatus comprising:a grinding mechanism for grindingcoffee beans placed therein; means for controllably dispensing beans tothe grinding mechanism; means for selecting a weight of ground coffeefor grinding by said grinding mechanism, said selecting means producinga first signal corresponding to the selected weight of coffee to beground; a receptacle cooperatively positioned relative to said grindingapparatus for receiving ground coffee from the grinding mechanism; meansfor weighing operatively associated with said receptacle for sensing theweight of ground coffee collected in said receptacle and producing asecond signal corresponding to the weight of the ground coffee; acontrol circuit coupled to said controllable dispensing means, saidselecting means and said weighing means, said control circuitcontrolling said controllable dispensing means as a function of acomparison of said second signal received from the weighing means andsaid first signal, said control circuit controlling said controllabledispensing means for decreasing the rate at which coffee beans aredispensed into said grinding mechanism as said first and second signalsapproach parity.
 4. A coffee grinder as recited in claim 3, furthercomprising said control circuit being coupled to said grinding mechanismfor stopping said grinding mechanism a predetermined time after parityof said first and second signals.
 5. A coffee grinding apparatus asrecited in claim 3, wherein said control means establishes a zeroreference point by weighing said receptacle before controlling saiddispensing means to dispense beans to said grinding mechanism such thatthe weight of the ground coffee is weighed by said weighing means.
 6. Acoffee grinding apparatus as recited in claim 3, wherein said selectionmeans is coupled to a beverage brewing apparatus such that selection ofa quantity of beverage to be brewed at said beverage brewing apparatusproduces said second signal corresponding to the weight of ground coffeeto be produced by said grinding mechanism.
 7. A coffee grindingapparatus as recited in claim 3, wherein said dispensing means includesa bean hopper operatively associated with an auger and a drive mechanismconnected to said auger and coupled to said control circuit forcontrollably rotating said auger.
 8. A coffee grinding apparatus asrecited in claim 7, further comprising said auger having a receiving endin communication with said hopper and a dispensing end in communicationwith said grinding mechanism, said dispensing end of said auger having asmaller outside diameter than a corresponding outside diameter of saidreceiving end for controllably dispensing beans to said grindingmechanism.
 9. A coffee grinding apparatus comprising:a grindingmechanism for grinding coffee beans placed therein; means for dispensingbeans to the grinding mechanism; means for selecting a weight of groundcoffee for grinding by said grinding mechanism, said selecting meansproducing a first signal corresponding to the selected weight of coffeeto be ground; a brewing funnel for use with a beverage brewing apparatusoperatively associated with said grinding apparatus for receiving groundcoffee from the grinding mechanism; means for weighing operativelyassociated with said receptacle for sensing the weight of ground coffeecollected in said brewing funnel and producing a second signalcorresponding to the weight of the ground coffee; a control circuitcoupled to said dispensing means, said selecting means and said weighingmeans, said control circuit controlling said dispensing means as afunction of a comparison of said second signal received from theweighing means and said first signal, said control circuit controllingsaid dispensing means for decreasing the rate at which coffee beans aredispensed into said grinding mechanism as said first and second signalsapproach parity.
 10. A coffee grinding apparatus as recited in claim 9,further comprising a funnel support structure operatively associatedwith said weighing means and said grinding mechanism for supporting saidfunnel proximate to said grinding mechanism to collect ground coffeedischarged from said grinding mechanism and weigh the ground coffee onsaid weighing means.
 11. A coffee grinding apparatus as recited in claim10, wherein said support structure includes two pivotable arms whichpivot outwardly to receive said brewing funnel, a lever memberoperatively associated with said grinder, said two pivotable armsdepending from said lever member, and said weighing means including aweight sensor operatively associated with said lever member for sensingthe weight of the ground coffee dispensed from said grinding mechanisminto said brewing funnel.
 12. A coffee grinding apparatus as recited inclaim 10, further comprising said weighing means being sufficientlyspaced from said grinder for accommodating a range of brewing funneldimensions, and said support structure including two displaceable railsoperatively associated with said weighing means, said displaceable railsbeing positioned relative to said grinder for positioning a mouth of abrewing funnel supported thereby proximate to said grinding mechanismfor collecting ground coffee dispensed therefrom.
 13. In a coffeegrinding apparatus for grinding whole bean coffee and discharging aprecise weight of ground coffee,a plurality of coffee bean hoppers; agrinding mechanism associated with each of said hoppers; means fordispensing beans to said grinding mechanism, said dispensing meansdispensing beans from an associated hopper; means for selecting a weightof ground coffee and a type of coffee bean for grinding by said grindingmechanism, said selecting means producing a first signal correspondingto the selected weight and type of coffee bean to be ground; areceptacle for receiving ground coffee from a grinding mechanism; meansfor weighing operatively associated with said receptacle for sensing theweight of ground coffee collected in said receptacle and producing asecond signal corresponding to the weight of the ground coffee; and acontrol circuit coupled to said selecting means, said weighing means andsaid dispensing means, said control circuit controlling said dispensingmeans as a function of a comparison of said second signal received fromthe weighing means and said first signal.
 14. In a coffee grindingapparatus as recited in claim 13, wherein said dispensing means includesa whole bean hopper in gravity relationship with said grindingmechanism, said grinding mechanism including a controllable motorcoupled to said control circuit.
 15. In a coffee grinding apparatus asrecited in claim 13, wherein said dispensing means includes a whole beanhopper in gravity relationship with a dispensing assembly, saiddispensing assembly being coupled to said control circuit forcontrollably dispensing beans from said hopper, said dispensing assemblydispensing beans from said hopper to said grinding mechanism.
 16. Acoffee grinding apparatus comprising:a plurality of coffee bean hoppersin a gravity feed relationship with a corresponding plurality ofgrinding mechanisms, each of said grinding mechanisms grinding coffeebeans from a corresponding one of said hoppers; means for selecting aweight of ground coffee for grinding by one of said grinding mechanisms,said selecting means producing a selected weight signal corresponding tothe selected weight of coffee to be ground; a receptacle for receivingground coffee from said grinding mechanism; means for weighingoperatively associated with said receptacle for sensing the weight ofground coffee collected in said receptacle and producing an actualweight signal corresponding to the weight of the ground coffee; asupport structure operatively associated with said weighing means, saidsupport structure supporting said receptacle for receiving ground coffeefrom said grinding mechanism; and a control circuit coupled to saidselecting means, said weighing means and said grinding mechanism, saidcontrol circuit activating and deactivating said grinding mechanism as afunction of said actual weight signal received from the weighing meansand said selected weight signal, said control circuit deactivating saidgrinding mechanism as said actual weight signal produced by saidweighing means and said selected weight signal approach parity.
 17. Acoffee grinding apparatus as recited in claim 16, further comprising asingle chute operatively associated with said plurality of grindingmechanisms for receiving ground coffee therefrom and delivering groundcoffee to said receptacle.
 18. A coffee grinding apparatus as recited inclaim 16, wherein said receptacle is a brewing funnel for use with abeverage brewing apparatus, said control means establishing a zeroreference point by weighing said brewing funnel before dischargingground coffee from said grinding mechanism, and a funnel supportstructure operatively associated with said weighing means and saidgrinding mechanism for supporting a funnel proximate to said grindingmechanism to collect ground coffee from said grinding mechanism andweigh the ground coffee with said weighing means.
 19. A coffee grindingapparatus as recited in claim 18, wherein said support structureincludes two pivotable arms which pivot outwardly to receive saidbrewing funnel, a lever member operatively associated with said grinder,said two pivotable arms depending from said lever member, and saidweighing means including a weight sensor operatively associated withsaid lever member for sensing the weight of the ground coffee dispensedfrom said grinding mechanism into said brewing funnel.
 20. A coffeegrinding apparatus as recited in claim 18, further comprising saidweighing means being sufficiently spaced from said grinder foraccommodating a range of brewing funnel dimensions, and said supportstructure including two displaceable rails operatively associated withsaid weighing means, said displaceable rails being positioned relativeto said grinder for positioning a mouth of a brewing funnel supportedthereby proximate to said grinding mechanism for collecting groundcoffee dispensed therefrom.
 21. A coffee grinding apparatus as recitedin claim 16, said means for weighing including weight sensorcomprising:a hollow housing and a cover, said hollow housing and coverdefining a cavity, said cavity retaining an incompressible liquid; aflexible diaphragm retained between said cover and housing in saidcavity and being operatively associated with said incompressible liquid;a contact body positioned between said cover and said diaphragm, a firstportion of said contact body abutting said diaphragm and a secondportion of said contact body extending through said cover, forcesapplied to said second portion of said contact body being transferred tosaid incompressible liquid; an electronic pressure sensing deviceoperatively associated with said incompressible liquid, forcestransferred through said incompressible liquid being sensed by saidpressure sensing device, said pressure sensing device generating ananalog signal proportional to the force applied to said contact body.22. A coffee grinding apparatus as recited in claim 21, furthercomprising a relief valve assembly operatively associated with saidhousing for releasing incompressible liquid from said cavity to relieveexcessive pressure in said incompressible liquid and prevent damage tosaid pressure sensing device.
 23. A coffee grinding apparatus as recitedin claim 22, said relief valve assembly further comprising a biasingdevice operatively associated with said pressure sensing device and saidhousing for biasedly retaining said pressure sensing device inassociation with said housing and in contact with said incompressibleliquid, said biasing device providing a biasing force which is less thana maximum allowable pressure on said sensing device.